Latency Help

I have a problem with latency. I am running an ASUS m45-1 Deluxe with AMD processor, 4G RAM and a 32G SSD. I am utilizing the only PCI slot for a parallel port and so I am using the onboard ATI Radeon video. I've disabled all power saving options in the BIOS as well as all unused peripherals (sound, USB3.0, etc.). I have pretty much disabled everything. However, my latency/jitter figures are around 100,000ns which I feel is quite high for this setup. I've read about many other similar setups achieving 1/3 to 1/10 this value.

I've been reading the many wiki entries and forum posts on this subject and have tried a number of them to fix my jitter issue. The one I seem to have the most difficulty with is the boot parameters. I've implemented the boot parameters through adding 07_rtai to /etc/grub.d and that didn't seem to work. As I understand it, by setting isolcpus=1 for my dual core processor, I should restrict all processes to 1 cpu. However, examining dmesg and even looking at the output of top, I see that it's utilizing both CPUs. Am I misunderstanding? I have also tried boot parameters by editing the GRUB config file. That yields the same result. Any thoughts on how I can confirm that the boot parameters are being interpreted?

you can see the booted kernel command line by typing:

Thanks! Indeed that shows that my isolcpus=1 parameter is not present and I now realize why. I forgot to run update-grub though I wouldn't expect to have to do that for the method outlined in the wiki article (07_rtai). Regardless, now that I have the parameters correct, things are looking a lot better. My jitter is now in the 15,000 ns range. I'll let this run for a good bit of time before I declare victory but thanks for the help!

Check your Bios again if it has an option "Patch AMD TLB Erratum". Ensure that it is ENABLED. This provided me roundabout -14.000 counters for the max_jitter (from ~22.000 down to ~8.000).

Regards
Michael